RFR: 8269838: BasicTypeDataBase.findDynamicTypeForAddress(addr, basetype) can be simplified

[Chris Plummer]

SA had a bunch of vtable related code that searched for the vtable pointer of a hotspot object in a few places. This was all related to weird ways that Solaris would store the vtable pointer. In the case of https://bugs.openjdk.java.net/browse/JDK-8269830, this extra vtable searching code introduced a bug in BasicTypeDataBase.addressTypeIsEqualToType(). Since we don't support Solaris anymore, this the bug was fixed by removing this Solaris support. At the time I fixed JDK-8269830, I noticed that BasicTypeDataBase.findDynamicTypeForAddress() had similar logic for vtable searching, although didn't seemed to be causing any bugs at the time. I filed JDK-8269838 to eventually clean it up, and that's what this PR is doing.

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Commit messages:
 - Strip out code that looks for vtable pointers in locations other than the 1st word of the object.

Changes: https://git.openjdk.java.net/jdk/pull/6827/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6827&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8269838
  Stats: 36 lines in 1 file changed: 0 ins; 28 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6827.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6827/head:pull/6827

PR: https://git.openjdk.java.net/jdk/pull/6827